1. Field of the Invention
The present invention relates to a process for the manufacture of fast dissolving compressed tablets with enhanced liquescent character and, in particular, to the use of a transitory liquid lubricant to produce fast dissolving compressed tablets.
2. Description of Related Art
It is desirable to provide liquescent or meltable tablets containing active ingredients which can be readily chewed or alternatively allowed to melt in the oral cavity. Such tablets have particular appeal for those consumers unable to swallow or chew conventional compressed tablets.
Prior to the present invention, it has been known to prepare tablet triturates which are soluble but very friable. The triturates are prepared by dampening a blend of a drub and diluent with ethyl alcohol containing varying quantities of water, forcing the dampened mass into holes in a forming plate, then pushing the mass out of the molds by push pins, and drying in ovens or heated tunnels. The finished tablet triturates are usually limited in size to about 250 mg and breakage from the ejection push pins is a problem as the size of the tablet is increased.
Tablet triturates formed on production equipment have an extremely high loss from tablet breakage with reject numbers running as high as 25-30%.
U.S. Pat. No. 4,684,534 describes a quick-liquefying chewable tablet characterized by a harder outer shell which inhibits penetration of liquid into the interior of the tablet, and a softer interior which quickly liquefies when the tablet shell is broken into pieces and contacted by a liquid. All of the examples in the patent describe tablets formed employing a relatively large amount of a non transitory metallic stearate lubricant. The tablet formulations described in the body of the patent are capable of improvement by substituting the liquid transitory lubricant of the present invention for the metallic stearate or other fat based lubricants disclosed in the patent. This patent is hereby incorporated by reference.
U.S. Pat. No. 4,810,307 describes a method for making a starch hydrolysate particle having increased bulk density and dissolution rate properties. Commercially available maltodextrin powder is subjected to roll compaction utilizing an amount of a liquid such as ethyl alcohol, acetone, hexane, cyclohexane, methyl ethyl ketone, etc. to form a damp powder blend. The blend is compacted between a pair of compacting rollers to form a sheet of material composed of formerly discrete maltodextrin particles crushed together with the liquid. The sheet is then broken into small particles and the remaining solvent removed by drying. The resulting particles are non-spherical and appear crystalline.
Maltodextrin agglomerates, compacts, or spray dried powders are unacceptable as the main excipient in a chewable tablet because the maltodextrin is a polymer and as such does not have the dissolution rate of a simple sugar such as mannitol or dextrose. The polymeric maltodextrin goes through a high viscosity stage in its dissolution and will stick to the teeth when chewed and in addition will demonstrate a dry then gelatinous mouth feel when chewed or sucked.
Bearing in mind the problems and deficiencies of the prior art, it is a primary object of the present invention to provide a method for making tablets by compression utilizing a transitory liquid lubricant and a special tablet formulation.
It is another object of the present invention to provide a method for making tablets by compression which are liquescent, meltable, or effervescent on conventional tablet compression machinery by the use of a transitory liquid lubricant.
It is yet another object of the present invention to provide a method for making tablets by compression which are liquescent, meltable or effervescent on conventional high speed tablet compression machinery containing therapeutic quantities of pharmacologically active substances.
It is still another object of the present invention to provide a method for the manufacture of an effervescent tablet on conventional tablet compression machinery by utilizing a transitory liquid lubricant that is removed after compression and which substantially obviates the need for special water soluble lubricants in order to ensure complete tablet dissolution following effervescence.
Another object of the invention is to provide tablets prepared by the method of the invention.
Still another object of the invention is to provide formulations which may be compressed into tablets.
Other objects and advantages of the invention will be readily apparent from the following description.